1. Field of the Invention
This invention relates to an insulation displacing barrel terminal having a first portion, a second portion and a connecting portion connecting said first and second portions, wherein said connecting portion is torsional to permit the first portion to rotate relative to the second portion in order to cause an insulated wire to be terminated in the terminal.
2. Description of the Prior Art
There are many instances where terminal blocks are set up and raised to receive insulated wires. Many of these terminal blocks are simply threaded members fixed with insulation material which receive wires either wrapped around the threaded members and secured thereto by an application of a nut, or the wires are terminated by known spade or ring terminals and then secured to the threaded member by a nut. While these have, in some instances, provided effective means for termination, they have not always been convenient for maintenance or repair, and they frequently are subjected to environmental degradation with a resulting loss of desired electrical characteristics. There is a need, predominantly within the telecommunications industry, for reusable terminals and terminals which can accommodate insulated wires having conductors of various sizes. For example, telephone wires coming from the telephone company, termed distributor wires, can either be in the form of multi-wire buried cable or aerial cable, which wires must be connected to particular wires extending to telephone at particular sites. The terminal blocks would be mounted in either an enclosure on the aerial mount, or in an enclosure pedestal affixed to the ground or on a pole. As new telephones are installed in a selective locality, an end of each phone wire is coupled or terminated to an appropriate terminal on the terminal block. There is also a need, particularly in applications where insulated wires are to be terminated in the field, that the conductors of the insulated wires be easily installed or affixed to the terminal. As many wires are required for operation, it is essential that the installation of the wires be accomplished with minimal effort and tooling. Generally, such terminal blocks include stub cables previously affixed thereto with discrete wires joined at one end to respective terminals in the block and the terminations sealed such as by potting; the terminated ends of the discrete wires of the stub cable are then to be spliced in the field to appropriate ones of the distribution wires outside of the terminal block.
The insulated wire sizes within the industry are not always the same gauge and therefore the terminals must be designed to accommodate more than one wire size. A typical size wire, running from the terminal block to the phone installation is copper-clad steel wire with a gauge of 181/2 AWG although other phone installations use copper wire having a gauge of 20-24 AWG. It can be appreciated, then, that a terminal having a higher quality means for terminating conductors, and having means to accommodate more than one insulated wire size, would be a substantial improvement within the industry. While the preferred embodiment of the terminal disclosed herein is for telecommunication applications, for example, for electrical interconnection of tip and ring signals, the invention could be used with other wire sizes and in other applications.
U.S. Pat. No. 4,431,247 shows an insulated terminal and module; however, the shell of the terminal includes only one wire opening for insulation displacement. Other previous designs are shown in U.S. Pat. Nos. 4,637,675 and 4,705,340 where stationary terminals are located within housings and rotatable caps are placed over the terminals. Rotation of the cap causes the wires within the caps to be rotated into the stationary insulation displacement portions.
Another previous design is shown in U.S. Pat. No. 5,006,077 which discloses a multiple-piece terminal which has a first section which remains stationary relative to a housing of the terminal and which also has separate rotatable sections which are rotatable on and relative to the first section.
The designs shown in U.S. Pat. Nos. 4,705,340 and 4,637,675 turn the wire into the slot which causes a bending of the wire. This bend, particularly in steel wire, causes a stored energy spring effect which can tend to become loosened over time.
The previous terminal designs shown in U.S. Pat. Nos. 4,705,340 and 4,637,675 are of one-piece construction and eventually become potted within a housing. The one-piece design leads to difficulty if one of the terminals becomes damaged and the terminals need to be replaced. To replace one of the terminals, the potting material has to be removed around the terminal, re-terminated to one of the telephone company wires, and then re-potted.
The U.S. Pat. No. 5,006,077 discloses a two-piece insulation barrel displacing terminal having a first cylindrical connector section coupled to an insulative housing. A rotatable section is mounted on the first section and rotated with respect thereto to terminate the conductor of the wire within the slot of the terminal. Another problem with the two-piece design of the '077 reference is that it was not uncommon that the electrical connection between the first section and the rotatable second section was not effective, for example, because the first and second sections would corrode. Also, because the second section remains fixed with respect to the housing, it could not terminate a wire in the same manner that a wire could be terminated in the first section.
While the previous versions are excellent designs, these designs include shortcomings which have been addressed by the instant design.